0. Virtual Richard M. Stallman (vrms)- The vrms program will analyze the set of currently-installed packages on a Debian system, and report all of the packages from the non-free tree (and, optionally, from contrib) which are currently installed.

2. Warsync- Warsync is a server replication system mainly used to sync servers in LVS clusters but also has many other uses. It is based on rsync over ssh and has native support for the Debian package synchronization.